Final answer:
The kinetic energy of a moving soccer ball changes as it gains or loses velocity, converting between kinetic and gravitational potential energy depending on its position relative to the ground.
Step-by-step explanation:
As a soccer ball moves, its kinetic energy changes depending on its velocity and height above the ground. When the ball is kicked and rises, it slows down, losing kinetic energy, and gains gravitational potential energy. Conversely, as the ball falls toward Earth, it speeds up, indicating an increase in kinetic energy as gravitational potential energy is converted back into kinetic energy. This exchange of energy occurs because the work done by the gravitational force is positive when the ball falls, as both the displacement and gravitational force point vertically downward.
According to the principle of conservation of energy, in the absence of friction and air resistance, the change in kinetic energy of a soccer ball is equal to the negative of the change in its gravitational potential energy. This principle explains why a soccer ball that is stuck into the ground after being thrown or a baseball hit by a bat can exhibit changes in momentum and kinetic energy, due to energy transfer during collisions.